Equipment Downtime Research Articles

Control system for thiosulfate leaching of intermediate industrial products in metallurgy

The efficiency of the process of thiosulfate leaching of intermediate industrial products depends on the composition of the incoming raw materials, the operational control of which is impossible. In this paper, we propose upgrading of the process control system which allows reducing the downtime of the process equipment.

Actual technical condition assessment of mine excavators’ slewing gear based on the operating oil parameters

During mining equipment operation, great attention should be paid to durability and reliability increase of their units and assemblies, since the greatest number of equipment failures in Kuzbass mines occurs precisely because of the failure of excavators’ slewing gears. Today this very problem is relevant for coal mining enterprises. One of the ways to improve the reliability of gears is the introduction of additional technological processes to diagnose the mechanisms actual technical condition of an excavator-automotive complex. However, the equipment and methods used do not fully meet the requirements for a comprehensive analysis of the technical condition of gears. Thus, there is a strong need to develop a modern technique to diagnose assemblies, based on the parameters of the operating oil. With the help of experimentally identified dependencies of the oil temperature in a gear on the parameters of the operating oil, a mathematical model of the wear process of slewing gears rubbing parts was obtained; the mathematical model has the possibility to predict possible failures of excavators. The introduction of this model in production will significantly reduce the downtime of mining equipment in coal mines; it also will affect the reduction of total costs of enterprises.

ANALYTICAL STUDIES OF STRAIN-STRESS DISTRIBUTION OF ROCK MASSIF AT RECOVERY ROOM T-JUNCTIONS

Russia’s coal industry has a clear trend towards increasing load on mining faces equipped by coal-face systems. With increase of coal-face equipment output, financial losses from the equipment downtime also increase. Downtime of fully-mechanized faces can have different causes, but downtime in disassembly is inevitable, and for this reason, minimizing downtime duration is paramount for improving mines operations efficiency. The main causes of repositioning duration increase are roofing rocks collapses into the work area, the most intensive collapse of roofing rocks occurs at the end sections of a recovery room. One of effective modes of enhancing the stability of roofing rocks is rocks destressing. The study objective is determining the parameters of destressing recovery room immediate roofing rocks in developing a gently-sloping thick coal seam on the base of the finite element mining and geomechanical model. The paper describes the methodology of developing a model and design models for assessing the components of the stress-strain state of the coal-bearing massif in the area adjacent to the recovery room. Assessment was conducted of the parameters of limit state zones in a coal seam and in the roofing rocks of the recovery room. Justification was provided for the parameters of the mode of immediate roofing destressing from the stresses at the end sections of the recovery room via drilling relief boreholes. The determined parameters of the technology include: the width of the destressing zone, the depth of the relief boreholes, their diameter, the boreholes’ spacing interval and the period of time until the passage of the longwall, for which they must be drilled.

ОПРЕДЕЛЕНИЕ КОМПЛЕКСНОГО ПОКАЗАТЕЛЯ ТЕХНИЧЕСКОГО СОСТОЯНИЯ ОБЪЕКТА НА ПРИМЕРЕ БЛОКА СТАБИЛИЗАЦИИ УСТАНОВКИ КАТАЛИТИЧЕСКОГО РИФОРМИНГА

Fail-safety taken as a factor of completeness of using the resources of the production facility is important for characterizing the technological process. In most modern automated process control systems the above factor is implemented by means of the emergency protection system which allows to avoid the progressing emergency. However, such measures significantly increase the downtime of process equipment, since the possibility of developing pre-emergency and emergency situations when combining several permissible and close to emergency values of parameters is not taken into account. To solve the problem of reducing machinery downtime, a method for determining the object state indicator has been proposed. It takes into account all variants of the influence of technological parameters on each other as well as their combinations leading to the emergency progress. As well, the proposed solution helps to set the proximity of the operating mode of the production equipment to the threshold emergency, which greatly reduces the risk of emergency in situ, thereby reducing equipment downtime and economic losses. The method of determining the indicator of the state of the object is considered on the example of the stabilization block of hydrogenate catalytic reforming unit.

Design of the Intelligent Manufacturing Demonstration System based on IoT in the Context of Industry 4.0

With the concept of German Industry 4.0, the Chinese manufacturing industry is in a critical period of restructuring and upgrading. With the gradual change of Chinese manufacturing industry from the mass and mass to the niche, personalized stage, the traditional rigid production system couldn’t make enough. This paper designed an Industry 4.0 intelligent manufacturing demonstration system based on Internet of Things. The system is based on the background of the model car assembly, which simulates the whole process of the delivery of the consumer from the single to the manufacturer. The vertical seamless integration of network production system is realized by getting through the information communication interface on the device layers between ERP and MES. The system adopts modular manufacturing mode, via WIA-FA and Software defined Control System technology, adjusting the production process dynamically, to achieve the function of scale production of customized products and the predictive maintenance of equipment etc. This system may reduce equipment downtime and improve equipment utilization, which solves the lower flexibility of the traditional rigid production system responding to the changing demands of design the production. It fully embodies the concept of Industry 4.0 in the smart factory.

Повышение срока эксплуатации литых броней из высокомарганцевой стали мельницы полусамоизмельчения

At the processing plants of the mining industry, a significant part of the total processing costs (from 45 to 65%) is spent on crushing and grinding operations, including mill lining. The efficiency of grinding equipment in the conditions of abrasive impact of ore and a continuous operation requires periodic replacement of a worn-out lining. The costs for its purchase, delivery and installation during a year amount to tens of millions of rubles, and the equipment downtime associated with the replacement of the lining reduces the volume of finished products by hundreds of millions of rubles per year. The practical efficiency of imported mill liners is not always confirmed by the expected positive result of their actual operation, and an increase in the equipment utilization coefficient (EUC), but their use definitely requires significant financial costs and entails risks in an unstable political and financial situation. Therefore, the task of increasing the service life of the mill liners is urgent. The paper presents a suggested and implemented solution to increase the lifetime of 110G13L steel lining for the wet semi-autogenous grinding mill (SAG mill-70х23). It includes monitoring of the actual liner operation and a mathematical simulation of the ore and ball trajectory in the mill, reveals zones of intensive wear, defects of liner castings and developed new structures of the lining elements. Applying the simulation software package, the authors studied the existing casting technologies, found reasons for defects and developed the casting technology for a new design of liners excluding defects. The paper contains industrial tests of the liners of a new design manufactured according to the developed technologies.

Exploring the Optimal Safety Person–job Matching Method of Major Equipment Based on Human Reliability

Under the background of intelligent manufacturing, this paper aims to develop a model for person–job safe matching that optimizes safety with consideration of major equipment operator competency and task complexity. Safe matching cost is minimized in the developed model and is measured by the equipment downtime, production defect rate, and operator labor costs oriented by human factors. Human reliability is calculated with the goal of best value individual competency and best admit task complexity with a hierarchical structure. The 0-1 integer programming person–job matching model minimizes the human factor safety and wage costs and satisfies the requirements of the production order, budget and operator quantity requirement. An improved genetic algorithm is designed to solve the model. The computational results of the proposed model based on a case study for a large iron and steel company evidently demonstrated its effectiveness. A new integrated model provides more realistic matches for person–job assignment.

Internet of Things enabling condition-based maintenance in elevators service

PurposeThe purpose of this paper is to demonstrate how Internet of Things (IoT) technology can enable highly distributed elevator equipment servicing by using remote-monitoring technology to facilitate a shift from traditional corrective maintenance (CM) and time-based maintenance (TBM) to more predictive, condition-based maintenance (CBM) in order to achieve various benefits.Design/methodology/approachLiterature review indicates that CBM has advantages over conventional CM and TBM from a theoretical perspective, but it depends on continuous monitoring enhancement via advanced IoT technology. An in-depth case study was carried out to provide practical evidence that IoT enables elevator firms to achieve CBM.FindingsFrom a theoretical perspective, the CBM of elevators makes business sense. The challenges lie in data collection, data analysis and decision making in real-world business contexts. The main findings of this study suggest that CBM can be commercialized via IoT in the case of elevators and would improve the safety and reliability of equipment. It would, thus, make sense from technological, process and economic perspectives.Practical implicationsOur longitudinal real-world case study demonstrates a practical way of making the CBM of elevators widespread. Integrating IoT and other advanced technology would improve the safety and reliability of elevator equipment, prolong its useful life, minimize inconvenience and business interruptions due to equipment downtime and reduce or eliminate major repairs, thus greatly reducing maintenance costs.Originality/valueThe main contribution of this paper lies in the empirical demonstration of the benefits and challenges of CBM via IoT relative to conventional CM and TBM in the case of elevators. The authors believe that this study is timely and will be valuable to firms working on similar research or commercialization strategies.

Оптимізація характеристик функціонування цехової служби технічного обслуговування деревообробного обладнання

Представлено подальший розвиток методики оптимізації характеристик цехової служби технічного обслуговування деревообробного обладнання. Теоретичною основою слугує теорія масового обслуговування. Потік відмов деревообробного обладнання розглянуто як однорідний, стаціонарний, без післядії. Такий потік називають найпростішим або пуасонівським. Цехову службу технічного обслуговування обладнання розглянуто як систему масового обслуговування, прийнявши, що інтенсивність відмов та інтенсивність обслуговування є постійними величинами. За відомими з теорії масового обслуговування залежностями визначено: середню довжину черги на обслуговування Мо; середню кількість замовлень Nз; середня кількість вільних робітників No; коефіцієнт простою робітників Ко; коефіцієнт простою замовлень Коз; коефіцієнт зайнятості робітників Кз. За мету оптимізації прийнято мінімум простоїв обладнання. За функцію мети оптимізації прийнято суму протилежних за характером зміни складових F = Мо + Nз + No ® min. Встановлено залежності характеристик функціонування цехової служби технічного обслуговування від кількості робітників бригади ремонтників. Дослідження функції мети на екстремум дає змогу визначити оптимальну чисельність робітників. Приклад розрахунку наведено для меблевого цеху на 25 одиниць обладнання.

Frost-Resistant Elastomeric Nanocomposites for Operation in the Far North Conditions

Operation of elastomeric materials in the extreme climatic conditions of the North is a complex and expensive, since not always existing materials can provide the required level of low-temperature characteristics (down to-60 ° C). This leads to failure of machines and mechanisms, equipment downtime, additional costs for repair or replacement of rubber parts. The need for such materials is continuously growing due to the intensive development of the northern territories, the need to develop new mineral deposits and development of offshore hydrocarbon production. Propylene oxide rubber (Tg = -73 °С) and epichlorohydrin rubber Hydrin T6000 (Tg = -60 °С) have unique frost resistance, but there is a need to improve aggressive media resistance, wear resistance and relaxation properties (the ability to restore its shape after relieving the load). For the modification of rubbers, additives of both organic and inorganic nature were chosen: ultrafine polytetrafluoroethylene, single-walled and multi-walled carbon nanotubes, nanodiamond-containing carbon charge obtained by detonation synthesis, shungite, natural zeolites and bentonite clays. The operating properties of rubber were studied in accordance with standard methods. The structure of the obtained materials was studied by means of DSC, XRD, electron and atomic force microscopy. All developed materials are recommended for use in various industries (oil and gas, road, rail) in the Arctic regions with extreme climatic conditions.

КОНТРОЛЬ ПРОПИТКИ – ЭФФЕКТИВНЫЙ ФАКТОР ПОВЫШЕНИЯ НАДЕЖНОСТИ ЭЛЕКТРОДВИГАТЕЛЕЙ ГОРНОДОБЫВАЮЩЕЙ, СТРОИТЕЛЬНОЙ И ДРУГИХ ОТРАСЛЕЙ ПРОМЫШЛЕННОСТИ

Отказ электрической машины приводит к аварийным ситуациям, к простою оборудования и, как следствие, к высоким экономическим затратам на ликвидацию результатов отказа машины. Наибольший ущерб отечественной экономике наносит отказ электрических машин при разведке, добыче и транспортировке георесурсов в нефтедобывающей, горнорудной, угольной, химической и других отраслях промышленности, так как эти отрасли в настоящее время являются основой формирования бюджета страны. Надежность и безотказность работы этих машин в значительной степени определяется технологическими операциями пропитки и сушки обмоток, так как на этих операциях формируются важнейшие качественные характеристики обмоток: электроизоляционные, тепловые, влагостойкие и механические. Все эти свойства зависят от степени заполнения межвитковых и прикорпусных полостей обмотки пропиточным составом. В случае некачественной пропитки обмоток возможно появление дефектов в межвитковой изоляции в период хранения и транспортировки оборудования к месту эксплуатации, что неизбежно приводит к снижению надежности изоляции обмоток. Совершенствование указанных операций невозможно осуществлять без надлежащих способов неразрушающего контроля качества проведения этой операции. Поэтому разработка методов контроля качества пропитки обмоток является весьма злободневной проблемой. Цель: показать возможность контроля распределенности пропиточного состава по обмотке по результатам измерения теплоёмкости обмоток до пропитки и после неё. Методы: электротепловые и электромагнитные, связанные с измерением тепловых параметров обмотки и отдельных электрических величин при контроле качества пропитки. Результаты. Рассмотрен электротепловой способ контроля качества пропитки обмоток. Обоснованы физические принципы контроля качества пропитки, и приведен вывод основных критериев оценки качества указанной технологической операций. Приведена схема прибора контроля, и рассмотрен принцип его работы. Произведен анализ погрешностей предложенного способа контроля.

Combining translation-invariant wavelet frames and convolutional neural network for intelligent tool wear state identification

On-machine monitoring of tool wear in machining processes has found its importance to reduce equipment downtime and reduce tooling costs. As the tool wears out gradually, the contact state of the cutting edge and the workpiece changes, which has a significant influence on the vibration state of the spindle. The performance of traditional intelligent fault diagnosis methods depend on feature extraction of dynamic signals, which requires expert knowledge and human labor. Recently, deep learning algorithms have been applied widely in machine health monitoring. In this paper, we present a novel intelligent technique for tool wear state recognition using machine spindle vibration signals. The proposed technique combines derived wavelet frames (DWFs) and convolutional neural network (CNN). Constructed based on dual tree wavelets, DWF are equipped with merits of centralized multiresolution and nearly translation-invariance. In this method, DWFs are employed to decompose the original signal into frequency bands of different bandwidths and different center frequencies, which are more pronounced as the tool wears. Further, the reconstructed sub-signals are stacked into a 2-D signal matrix to match the structure of 2-D CNN while retaining more dynamic information. The 2-D convolutional neural network is utilized to automatically recognize features from the multiscale 2-D signal matrix. End-milling experiments were performed on a S45C steel workpiece at different machining parameters. The experiment results of the recognition for tool wear state show the feasibility and effectiveness of the proposed method.

Design and approval third party audit of material handling and mining equipment

Specialised mining and material handling equipment such as stackers, reclaimers, bucket wheel excavators, etc. require special attention during the design and manufacturing stages. The third party audit conducted by independent expert plays an important role in the entire delivery process. Although the use of a third party auditor is recommended by different standards, it is not a mandatory step that will ensure a design and manufacturing crosscheck. It appears, however, that more and more complex industrial projects utilise this process, which may consist of design and manufacturing check, erection and performance tests supervision and final approval of the equipment. Although it may slightly increase the initial costs of the project, it is beneficial as it decreases future investments and downtimes of equipment. In this paper, the authors present recommended scope of third party audit of mining and material handling equipment and their experiences gained during many projects completed in this field.

Assessing Facility Maintenance Models for Data Centres: Status and Deficits of Current Facility Management and Maintenance Concepts

According to studies conducted by Information Technology (IT) analysts, the average cost per minute of IT equipment downtime is about $7,900, depending on the sector the company is active in. The average reported incident length is 86 minutes, resulting in average costs per incident of approximately $690,200 . This illustrates that failure in the operation and maintenance of Data Centre (DC) infrastructure has enormous impacts and consequences. Facility Management (FM) in data centres requires a broad and clear understanding of procedures and processes to avoid human errors and to ensure an economic and reliable operation of the clients’ primary activities. In the DC-industry, availability is the most important factor followed by economical aspects. Therefore, both research and implementation of stable processes with an optimal number of interfaces between IT related functions and FM are necessary to increase the effectiveness and efficiency. Therefore, this paper explains the settings of current FM and maintenance concepts used by the DC-industry. Furthermore, the need for a more innovative approach to ensure an economic and reliable operation of DC in the future is introduced. A special emphasis is on a review of the current status and deficits of facility maintenance und management concepts for DC providing direction for future research. It seems that maintenance has developed from an operational, technically-based activity to a strategically important management function.

Ensuring the operability and fault tolerance of machinery by redundancy of replaceable elements

The main task in mechanical engineering is to ensure the efficiency of the machine-tractor fleet. Technical operation of machines requires new organizational and technological approaches to maintaining it in working condition in zonal conditions of use. Since every hour of downtime of this expensive equipment leads to high costs, one of the important tasks will be to reduce the downtime of machines for maintenance and repair. Development of import substitution programs and food security of regions and regions of the country is an important area for scientific and public organizations to solve the tasks set by the government of the Russian Federation. In this regard, the study of foreign technologies and the introduction of their own in the production of machinery and agricultural products. The aim of the study is a mathematical description and justification of fault tolerance of machines to ensure performance at a given level.In the article deals with the issues of ensuring the efficiency of technical systems (machinery and equipment) and planning the number of spare elements during technical service. It is rather simple to establish the cycles of repair time of machines and technology, if the variables of the technical state determining the operability of the machines during operation are deterministic. In practice, in most cases, the performance is determined by the stochastic nature of the influencing factors, forcing to take into account the technical and mathematical methods for their description. In a situation where the recovery time of the failed element is an order of magnitude shorter than the uptime, or the restoration is reduced to replacing the element with a backup, it is natural to accept the model of an instantly restored element.

Reducing the energy consumption of the conveyor transport system of mining enterprises

The article deals with the actual issue of reducing the energy consumption of the mining enterprises conveyor transport system. The analysis of energy loss by conveyor belt during transportation of bulk load is given. A comparative analysis of energy losses in the cases of regulation and non-regulation of the speed of the conveyor belt is given. It was found that when regulating the speed of conveyor belt in the case of reducing the value of the load flow entering to the conveyor by half the loss of electricity for the transportation of load is reduced by 30 % compared to the unregulated speed of the belt. The energy efficiency criterion of the conveyor transport system is determined, which coincides with the specific energy capacity equal to the ratio of the average energy capacity of the transportation of load to the transport system average carrying capacity. It has also been established that for conveyor transport systems conveyor– bunker–conveyor, taking into account the downtime of conveyor equipment while regulating the speed of conveyor, energy losses are reduced by 23 %. The research results can be used to create a computer control system for the operation of conveyor transport systems.

Machine Learning Framework for Predictive Maintenance in Milling

Abstract In the Industry 4.0 era, artificial intelligence is transforming the manufacturing industry. With the advent of Internet of Things (IoT) and machine learning methods, manufacturing systems are able to monitor physical processes and make smart decisions through realtime communication and cooperation with humans, machines, sensors, and so forth. Artificial intelligence enables manufacturers to reduce equipment downtime, spot production defects, improve the supply chain, and shorten design times by using machine learning technologies which learn from experiences. One of the last application of these technologies is the development of Predictive Maintenance systems. Predictive maintenance combines Industrial IoT technologies with machine learning to forecast the exact time in which manufacturing equipment will need maintenance, allowing problems to be solved and adaptive decisions to be made in a timely fashion. This study will discuss the implementation of a milling Cutting-tool Predictive Maintenance solution (including Wear Monitoring), applied to a real milling data set as validation of the framework. More generally, this work provides a basic framework for creating a tool to monitor the wear level, preventing the breakdown, of a generic manufacturing tool, in order to improve human-machine interaction and optimize the production process.

Durability of cutter assemblies and its causative factors

Cutter assemblies operate under stressful conditions: the knives are subjected to high dynamic loads, the cutter shaft rotates at a frequency of 5–100 s-1, the electric driving motor of the cutter shaft overcomes high starting moments, the bed is subjected to significant static and dynamic loads, the food raw materials and humid atmospheric air in the production room is corrosive to the structural elements, etc. Under the influence of these factors, the cutter assemblies break down, which causes unregulated pauses in food raw materials processing and also requires high expenses for equipment repair. The aim of the paper was to study the durability of the main cutter assemblies and to establish its main determining factors. The presented numerical values of durability of cutter assemblies have been obtained as a result of the planned, warranty and post-warranty practical maintenance of cutters by the engineering team of GEA FOOD SOLUTIONS UKRAINE, LLC, the mechanical supervisor staff of Cherkassk Food Company, LLC and also as a result of scientific research of the processes that provide the operation of these machines and that were carried out at the Cherkassy State Technological University (the Ukraine). The components that operate under the most stressful conditions are knives, a cutter shaft and its bearing assemblies, and the electric driving motor of the cutter shaft. At the same time, the durability of most cutter assemblies is limited by the quality of operation of the cutter head and the durability of the knives. The expenses for the repair or replacement of cutter assemblies can amount to tens of thousands of euros (not including the losses caused by equipment downtime). By applying the appropriate technical solutions and cutter system operating rules, it is possible to significantly improve the durability of a cutter and reduce these expenses.

Modernization of No. 23 runway drives of 2800 HSM at sheet-rolling shop (LPZ-1) of JSC “Ural Steel”

Increasing of rolling and adjacent equipment operation reliability, decreasing of its emergency downtime, increasing of overall periods duration are actual tasks of personal of any sheet-rolling plant.Using data of the register of 2800 HSM of sheet-rolling shop (LPZ-1), JSC “Ural Steel”, the number and duration of downtimes of the mill No. 23 runway analyzed, caused by runway drive tooth coupling failure. The main reasons of tooth coupling failure determined. Modernization of No. 23 runway drives proposed, being its design modification by introducing of cardan shaft for rollers drives. This enabled for giving up the tooth coupling usage, pushing away the electric motors, that avoided water drops and vapor on them hitting, decrease unplanned equipment downtime. Certain parameters of drives determined and calculation of technical and economic indices before and after the runway drives modernization presented. The implementation of modernization actions resulted in a decrease of No. 23 runway repair and maintenance expenses, including the purchase and installation of the tooth coupling. The expenses for No. 23 runway drives modernization made1.7 mil Rubles and the payback period – 6 months.

Lean implementation for rail substation processes

PurposeTraction substations are an integral part of the railway infrastructure. In order to ensure that machinery and equipment is available and utilised at full capacity, intelligent maintenance methods should be implemented. The purpose of this paper is to focus on the development of lean maintenance strategies implemented on traction substations and offer the maintenance manager an alternative maintenance method to be utilised during optimisation initiatives.Design/methodology/approachThe rail company under consideration has various improvement options, the maintenance supply chain is a priority. The existing maintenance process of 3 kVDC traction substations is examined and all operations and activities directly and indirectly associated with maintenance are analysed with lean methodologies. The analysis of maintenance operations and activities reveals that some of these operations and activities are non-value-adding and, therefore, regarded as waste. These activities only prolong the maintenance process without adding value to the process. Alternative operations and activities are suggested and simulated.FindingsThe application of lean indicates that the maintenance process could be optimised to deliver on a more efficient process, which would improve the quality of maintenance by ensuring that maintenance is timeously carried out. Through reducing the downtime caused by maintenance, the availability of the system is preserved and the railway lines could be used to capacity.Research limitations/implicationsThe research is limited to 3 kVDC traction substations and the associated maintenance process, as this was the area of opportunity for the company. The track and overhead traction equipment maintenance is not included.Practical implicationsThe practical application of this research is in optimisation of the value chain for maintenance, specifically in the rail industry.Originality/valueThis research could be applied by maintenance managers to effectively implement if a run-to-failure (RTF) maintenance philosophy is being utilised. The research offers maintenance techniques within the RTF maintenance scope which reduces the maintenance cycle and equipment downtime.